Closed fluid-operated free-pump system with two parallel tubings, one of which encloses a third tubing



March 18, 1952 c. J. coal-:RLY

CLOSED FLUID-OPERATED FREE-PUMP SYSTEM WITH TWO PARALLEL TUBINGS ONE OF' WHICH ENCLOSES A THIRD TUBING 2 SHEETS-SHEET 1 Filed May 16, 1949 80 6/789 4254248 90 ik i933 CLOSED FLUID-OPERATED FREE-PUMP SYSTEM"A` WITH TWO PARALLEL TUBINGS ONE OF WHICH ENCLOSES A THIRD TUBING Filed May 16, 1949 2 SHEETS- SHEET 2 March 18, 1952 l c. J. `coal-:RLY 2,589,670

EWI

Patented Mar. 18, 1952 CLOSED FLUID-OPERATED FREE-PUMP SYS- TEM WITH TWO PARALLEL TUBINGS, ONE OF WHICH ENCLOSES A THIRD TUBING Clarence J. Coberly, Los Angeles, Calif., assigner, by mesne assignments, to Dresser Equipment Company, Cleveland, Ohio, a corporation of Ohio Application May 16, 1949, Serial No. 93,482

31 Claims. 1

' My invention relates in general to tubing systems for uuid-operated well pumps and. more particularly, to a closed tubing system for a fluidoperated well pump of the so-called free type.

Reference is hereby made to my copending applications Serial No. 93,483, led May 16, 1949, Serial No. 93,484. filed May 16, 1949, and Serial No. 93,481, led May 16, 1949.

It is conventional in the oil industry to employ a well pumping apparatus which includes a free fluid-operated pump, such a pump being movable into and out ofthe well through a tubing set in the well and being adapted to assume an operating position at the lower end of such tubing. Examples of such huid-operated, free-pump systems are disclosed in my Patent Nos. 2,230,830, granted February 4, 1941, and 2,338,903, granted January 11, 1944.

In conventional fluid-operated, free-pump systems, such as those disclosed in ,my aforementioned patents, two tubings are employed, one for conveying operating fluid downwardly in the well to the pump and the other for conveying iiuid produced by the well upwardly therein from the pump to the surface, the two tubings being referred to hereinafter as the supply and production tubings, respectively. In such conventional systems, the pump is movable into its operating position through the supply tubing. The supply and production tubings are interconnected at their lower ends in fluid communication with each other and with the well so that the pump may receive operating fluid from the supply tubing and well iiuid from the well and so that it may dischargewell uid into the production tubing as production fluid.

In installing such a free pump in the well, it is moved downwardly through the supply tubing into its operating position atthe lower end thereof either by the action of gravity or by the application of uid pressure to the upper end of the pump. After the pump has been installed in its operating position, operating fluid, which is usually clean crude oil, is delivered to the motor section of the pump under relatively high pressure through the supply tubing. As is well known in the art, such operatinguid is alternately directed by a suitable valve mechanism in the motor section of the pumpto opposite ends of a motor piston which is coupledto apump piston in the pump section of the device, fluid from the well being admitted to the pump section by a suitable valvemechanism therein.4 Such a1- ternating application of operating fluid pressure to the ends of the motor piston produces reciprocation of the motor and.` pump pistons with the result that the pump piston pumps fluid produced bythe well into'the production tubing, the latter conveying the production qiud upwardly therein to the surface.v l" When removal-f the pump from the well is desired for any reason, as for service or repair, uid pressure-is applied to the lower end of the pump to move it upwardly out of its operating position and through the supply tubing to the surface. This is accomplished by conventionally reversing the flow through the system so that operating uid flows downwardly in the production tubing to the lower end of the pump and acts on the pump to move it upwardly through the supply tubing to the surface.

In a conventional free-pump 'system of the foregoing character, the spent operating fluid discharged by the motor section of the .pump is delivered to the production tubing so that the spent operating fluid and the production fluid are intermixed and conveyed upwardly together through the production tubing. Since the operating fluid delivered to the pump through the supply tubing must be clean, in order to prevent abrasion and corrosion of the moving parts of the pump, fresh operating iluid must be supplied to the system continuously. The continuous provision of such fresh operating fluid requires considerable surface equipment, normally in the form of settling tanks or filters, which is expensive to install and operate. Also, in the particular arrangement hereinbefore mentioned wherein-the pump is disposed in the supply tubing, the flow reversal'necessary to remove the pump from the well may carry any sand or other foreign matter present in the production fluid into the supply tubing with the result that such foreign matter may enter the motor section of the pump upon resumption of operation after reinstallation with the attendant possibility of damage to the Dump- In View of the foregoing, it is a primary object of this invention to provide a closed system for the duid-operated, free pump which includes a third tubing separate from the supply and production tubings for returning the spent operating fluid to the surface independently of the well fluid, the tubing for returning the spent operating fluid being referred to hereinafter as the return tubing. With such a closed system, the spent operating fluid is separately conveyed back to the surface for storage and re-use to actuate the fluid-operated pumpso that there is very little loss of operating fluid from the system and. consequently, the surface equipment necessary to supply fresh operating fluid to the system needs have only a relatively small capacity and can be relativelycheap and economical, both as regards initial cost and operating costs. Also, the reversed flow `necessary to move the pump upwardly to the surface during removal of the pump may take place through the return tubing to avoid carrying said and other foreign matter into that portion of the system reserved for the operating iiuid, which is an important feature.

rangements employed to provide such a closed system.

Considering the invention more specifically, an object thereof is to provide a closed 'system for a fluid-operated, free pump comprising supply, return and production tubings which are set in the well and one of which is adapted to receive the pump and to provide an operating position for the pump at its lower end, the supply, return and production tubings respectively being adapted to convey operating fluid for actuating the pump downwardly into the well to the pump, spent operating fluiddischarged'by the pump up- Wardly in thewell'from the .pump to the surface and production uid discharged by the pump up- `'vvardlyin :the'wellfrom th'epump to the surface.

An `infiportan't object of the invention is to pro- -vide ya closed system wherein the supply, return and production tubings are set in the well with one Lof lthe tubin'gs ydisposed within another. A further object yin this connection .is to provide a closed system wherein-one ofthe tubings is disposed -within a-second and wherein the third tubing vis disposed beside the second. y

Another Objectis vto'provide such a closed system wherein the three tubings are interconnected attheirlower ends in iiuid communication with eachother and with the well 'so that the pumpv may, when inits operating position, receive oper- :ating uid vfor its actuation from'the supply tubing through'an intake, discharge spent operating fluid finto the `return tubing through an exhaust, receivewell liluid from the well through an inlet and discharge 'well fluid into the production tub- -ing through 'an outlet.

-Another object is to provide a Vclosed system having 'means whereby a doW-nward flow of iuid through one of the tubings, other than the tubing in which the pump is disposed, may be applied to thelower end ofthe pump to move it upwardly Jout of its Voperating position and through the tubing in-wh`ich it is disposed to the surface when'- e'ver removal 'of the pump lfrom the well is desired. ,y Another 'object is to provide a closed system which l'includes a tubular pump receiver disposed at the lower Iend of "and rin alignment with the tubing through which'the pump is movable, the pumpreceiver being, in elect, an extension of suchtubin'g and providing the aforementioned operatingl position for the pump. A related object is to provide a pump receiver having a seat at its lowerjend for the pump, the pump being seated on such seat *when it is in its operating position. Anothervobject is to provide a pump receiver having passages which vplace the interior 'thereof `in uidjcommunication with the supply, return and production tubings and with the well in such a mannerV as to provide uid communication between the intake, the exhaust, the inlet and the outlet ofthe pump and the supply tubing, the return tubing, Ithe weiland the production tubing, respectively, when the pump is disposed in the pump receiver and seated on the pump seat.

Another object is to provide sealing means for normally preventing direct ow between the tub# ings and -the well by way of the pump receiver when the pump is in its operating position so that operating iiuid may owonly from the supply tubing through the motor section of the pump to the return'tubing and sojthat -Ywell fluid 4mayow only v'from ''shewell throug'hthe pump section vo'i Y y 4 l the 'pumpto the production tubing. More specifically, an object in this connection is to provide a sealing means which, when the pump is in its voperating position, places the supply tubing in luid communication with only the intake of the pump, the return 'tubing in fluid communication with only the exhaust of the pump, the well in fluid communication with only the inlet of the pump and the production tubing in fluid communication with only the outlet of the pump.

Another object is to provide a system wherein the aforementioned sealing means comprises annular sealing elements which are carried by the pumpadjacent various of the ports, suchas the intake, exhaust, etc., therein and which are engageable with the inner wall ofthe pump receiver to preventrdirect flow betweenthe tubings.

Another Iobject -is'to provide passage means communicating at one end .with one ofthe -tubings, otherthanfthe -tubing aligned -with the pump receiver, and at :its other -end with -a lchamber in the pump receiver'between the jpump seat vand the pump for applying "a downward iiow of iiuid through such tubing tothe lower end of the pump to move it upwardly outof the pump receiver and to the'surface. Y

Another object is to'provide a-sealing device for normally preventing `iiuidilow between two of the tubings by way of the aforementioned passage means and the pump receiver when the pump is in its operatingposition. Another object in this connection is to provide va system wherein the aforementioned sealing device is an'annular sealing element adapted to be disposed between the pumpand the pump receiver.

Another vobject is to provide a system wherein the tubing with which the-aforementioned passage means communicates is the return tubing so that the pump may be moved upwardly to the surface by a downward ow of clean fluid through the return tubing to .prevent introducing sand and other abrasive matter into the pump receiver.

Still another object is to provide a closed system wherein -the pump is movable into its operating position in the pump receiver through the supply tubing and wherein the pump is movable upwardly to the surface lby a downward ow -of clean fluid through :the return tubing -so as to avoid carrying any of the'sand'or other abrasive material which may be in the fluid in 1the-production tubing into the pump 'receiver-during the pump-removal operation. i

Another object is to provide aclosed system in 'which damage .from any corrosive substances in lthe production fluid `is minimized by permitting the production iiuid to come incontact with only the production tubing. Thisis accomplished by locating the supply and return tubings without theV production tubing, which is an important fea-- ture.

Another object is to minimize the power -required to overcomefriction between 'thelproduction fluid moving Vupwardly through thejproduction tubing and the Wall of the production tubing by employing a production tubing havingalarge internal diameter. This feature is ,particularly important under well conditions such that 'apump 'having a motor section ofsmall vcapacity Aand :a pump section of Vlarge capacity'maybe employed. Another object is to maximize the 'external diameter of the pump by making th'etubing for receiving the pump of large "internal diameter. This permits the ,employment .of a .pump having motor 'and/or pump v'sections of maximum capacity. whichis1animportantfeature.

which vare illustrated in the accompanying drawings and'which are described in detail hereinafter. Referring to the drawings:

Fig. 1 is a utility View of a closed, fluid-operated, free-pump system which embodies the invention;

Fig. 2 is an enlarged, horizontal sectional view taken along the broken line 2-2 of Fig. l;

Fig. 3 is an enlarged, vertical sectional view taken along the broken line 3-3 of Fig. 2.

Fig. 4 is a downward continuation of Fig. 3;

Fig. 5 is a utility View of another embodiment of the invention;

Fig. 6 is an enlarged, horizontal sectional view taken along the broken line 6 6 of Fig. 5;

Fig. 7 is an enlarged, vertical sectional View taken along the broken line 'I-l of Fig. 6; and, Fig. 8 is a downward continuation of Fig. 7.

Considering first the embodiment illustrated in Figs. l to 4 of the drawings and referring particularly to Fig. l thereof, the numeral I5 designates .a well casing which is set in an oil well with its lower end open to an oil producing formation adjacent the well as is well known in the art, the casing being 'provided with a casing head I 6 at its .upper end. Set in the Well within the casing I5 and connected to the casing head I6 is a closed tubing system of the invention which comprises supply, return and production tubings respectively designated by the numerals I 'I, I3 and I9. The tubings II, I8 and I9 are interconnected at their lower ends in fluid communication with each other and with the well by a tubular pump receiver 20 which is aligned with and which, in effect, forms a downward extension of one of the tubings. In the particular embodiment presently under consideration, the pump receiver 20 is aligned with the supply tubing II, the supply tub-y ing being concentrically disposed within and spaced from the return tubing I8 and the production tubing I9 being disposed beside the return tubing. The pump receiver 20 provides an operating position for a free Huid-operated pump 2| .which is movable downwardly through the -supply tubing II into its operating position in the pump receiver, the internal diameter of the pump receiver being substantially equal to that of the supply tubing. As will be discussed inmore detail hereinafter, the supply tubing I1 is adapted to convey operating fluid, such as clean crude oil, under pressure downwardly in the well from the surface to the pump 2I to actuate the pump, and the return tubing I8 is adapted to receive spent operating fluid discharged by the pump and to convey the spent operating liuid upwardly around the supply tubing I'I to the Surface. The pump V2I is adapted to receive well fluid from the well and to discharge it into the production tubing I9 as production iluid, the production tubing conveying the production uid upwardly in the well to the surface. e

In the particular construction illustrated, the lower ends of the tubings Il, I3 and I9 and the pump receiver 29 are enclosed by a gas anchor 22 having aV perforated barrel 23 which is'l'closed at its'. upper and lower ends'by heads 24 and 25, respectively, the upper headhaving suitable openings therethrough for the tubings.

The gas anchor 22 is secured to the pump receiver 20 by a bolt 25 connecting the lower head 25 to the pump receiver.

The supply, return and production tubings Il, I8 and I9 are connected at their upper ends to a pump head 29 having valve means (not shownl' therein which is operable from the surface by a handle 30 to direct flows of fluid through the tubing in the proper manner as will be discussed in more detail hereinafter. Also connect'-v ed to the pump head 29 are supply, return and production lines 3|, 32 and 33 which, during operation of the pump -2 I, are adapted to be connected in liuid communication with the supply, return and production tubings I'I, I3 and I9, respectively, by the/valve means in the pump head. The supply line 3l leads to a suitable source (not shown) of operating fluid under pressure, which source may be a conventional triplex pump having its intake connected to a suitable reservoir. The return line 32 leads to the reservoir and the production line 33 leads to a suitable point of disposal or storage for the production iuid. As disclosed in my aforementioned Patent No. 2,338,903, the pump head 29 may also include a suitable pump catcher (not shown) for the pump 2l, thelatter having at its upper end a tapered head 35 which is receivable by the pump catcher during removal of .the puni-'p from the well.

Referring now to Figs. 3 and Ll of the drawings, the pump receiver 23 is, as previously indicated, aligned with the lower end of the supply tubing il; the pump receiver having at its upper end inner and outer .sleeves 3B and 39 which are concentrically arranged in spaced relationship and which register with the supply and return tubings I1 and I8, respectively. Disposed below and registering with the inner and outer sleeves 38 and 39 are inner and outer sleeves 40 and 4I, respectively, the sleeves 40 and 4I being arranged concentrically in spaced relationship. Disposed below and registering with the sleeves 40 and 4I, respectively, are inner and outer sleeves 42 and 43 which are concentrically arranged and spaced apart. The lower ends of the supply and return tubings I'I and I 8 and the ends of the pairs of sleeves 33 and 39, 49 and 4I, and 42 and 43 are beveled in such a manner as to form conical surfaces. The conical surface at the lower ends of the supply and return tubings I-.'I and I8 and the conical surface at the upper end of the pair of sleeves 33 and 39 are seated against opposite sides of a spacer 45 having two complementary conical surfaces. Another spacer 45 is disposed between the pair oi sleeves 3e and 39 and the pair of sleeves i9 and il and still another spacer 45 is disposed between the pair of sleeves 40 and 4I and the pair ci sleeves 42 and 43. The conical surface at the lower end of the pair of sleeves 42 and 43 is seated against a complementary conical surface 46 formed at the junction of a major bore 4l and a counterbore 48 in a tting 49 forming part of the pump receiver 20, the lower end of the outer sleeve 43 being threaded into the counterbore 48. The outer sleeve 39 and the return tubing I3 are threadedly connected by a coupling 59 and. the

'outer sleeve 39 and the outer sleeve 4I are threadedly connected by another such coupling. Still another coupling 50 threadedly connects the outer sleeve 4I to the outer sleeve 43.

It willbe apparent, that, withthe foregoing intake 18 and the exhaust 8| when the pump 2| is in its operating position so that the intake may communicate only with the supply tubing I1 and soy that the exhaust may communicate only with the return tubing.

As previously indicated, the pump section of the pump 2| is provided with an inlet at its lower end through which well fluid is adapted to enter the pump section by way of the inlet fitting 12, the inlet of the pump not being shown specifically. The pump section of the pump is also provided with ports forming an outlet 88 for production uid discharged by the pump section, the outlet communicating with an annular'space 89 around the pump. The annular space 89 communicates with the'lateral passage 56 connecting the interior of the pump receiver 20 with the minor bore 55 in the fitting 49 so that production iiuid discharged through the outlet 88 may enter the production tubing I9.

It will be noted that the annular sealing element 81 is disposed between the exhaust 8| and the outlet 88 so that it prevents flow between the return and production tubings I8 and I9 when the pump is in its operating position. Also, since the pump 2| is seated o n the inlet fitting lateral passage 56 therein when the pump is in pits operating position. Thus, the annular sealing element 9U also serves to isolate the production tubing I9 from the return tubing I8 when the pump is in its operating position. A

Considering the operation ofthe embodiment of the invention hereinbefore described, it will be assumed that the pump 2| is in operation to pump fluid from the well upwardly through the production tubing I9 to the surface. Under such conditions, the pump 2| is in its operating position in the pump receiver 28 wherein it is seated on the inlet fitting 12, and the aforementioned valve means in the pump head 29 respectively connects the supply, return and production tubings I1, I8 and I9 to the supply, return and production lines 3|, 32 and 33. Thus, operating fluid under pressure is conveyed downwardly to the pump 2| through the supply tubing I1 and enters the motor section of the pump through the intake 78 to actuate the pump, spent operating fluid being discharged into the return tubing I8 through the exhaust 8| and beingconveyed upwardly in the well to the surface by the return tubing. The well uid entering the pump section of the pump 2| through its inlet is discharged into the production tubing I8 through the outlet -88 and is conveyed upwardly in the well to the surface as production fluid. It will be apparent that, with this construction, the spent operating uid is returned to the surface separately from the production fluid .so that it may be re-used to actuate the pump 2|, which is a primary feature of the invention.

In the event that removal of the pump 2| from the well is necessary in order to service or repair the pump, or for any other reason, the operator sets the handle 30 controlling the valve means in the pump head 29 in a position such that the valve means connects thel supply line 3| to the return tubing I8 so that the operating fluid under pressure now iiows downwardly into the well through the return tubing. Preferably, the valve means also connects the supply tubing I1 to the return line 32 under such conditions, and prevents fluid communication between the production tubing I9 and the production line 33? Alternatively, fluid now through the production tubing I9 and the production line 33 may be prevented by closing a valve 94 in the production line 33.

Under the conditions outlinedD in the preceding paragraph, operating fluid under pressure ows downwardly through the return tubing I8 and into the annular chamber 68 at the lower end of the pump 2l by way of the return passage 5| and the passage means 58. The. pressure of the operating fluid entering the annular chamber 69 in the foregoing manner is applied to an annular area at .the lower end of the pump 2| so as to unseat the pump from'the inlet fitting 12 and is then applied to the entire area of the pump so as to move it upwardly in the pump receiver 29, upward flow of the operating fluid applied to the lower end of the pump in this manner past the pump being prevented by the annular sealing elements r86, 81 and 90. After the pump 2| has moved upwardly in the pump receiver 28 a distance such that the annular sealing elements 88 and 81 disengage the intermediate inner sleeve 4i) and the annular sealing element 98 disengages the liner 9|, upward now of operating uid past the pump is prevented bypacking devices 96 and 91 which are carried by the rod 89 and'which are adapted to engage the inner wall of the supply tubing I1 in a substantially uid-tight manner, the portions of the lpump 2| whichrcarry the annular sealing elements Se, B1 and 90 preferably being of smaller diameter than the internal diameter of the supply tubing so las to prevent damage to these sealing elements during movement of the pump through the supply tubing. After the pump has cleared the ports 83 in the intermediate inner sleeve 48, the downward ow of operating uid through the return tubing I8 is applied to the lower end of the pump directly through such ports.

During the foregoing pump-removal operation,

ow of the operating fluid employed to remove the pump out of the pump receiver into the well is prevented by the check valve in the inlettting 12 and iiow thereof into the production tubing 9 is prevented because -iiow through the production tubing is prevented by closing the aforementioned valve 94, or by means of the valve means inthe pump head 29. Itwill be noted that', since the standing valve 63. prevents downward flow ofl the production fluid out of the production tubing I9 -and into the pump receiver, none of the production iiuid can enter the pump receiver during the pump-removal operation, which is an important feature since it prevents sand land other foreign `matter which may be in the production fluid from entering the pump receiver. Thus, any possibility of suchforeign matter entering the motor section of the pump 2| Vupon reinstallation thereof is prevented, which eliminates possible damage to the motor section from this source. v

It will be noted that, under the conditions hereinbefore outlined, the operating fluid in the supply tubing l1 above the pump 2| is returned to the reservoir through Vthe return line 32 during the pump-removal operation so that substantially none of it is lost from the system, which is an important feature. As will be understood, when 4thes'pump 2| reaches the surface, 'it is caughtby the laforementioned pump catcher in the pump head 29 and may subsequently be remove'd through the pump head.

VWhen reinstallation of the pump 2|, 'or-'instal-V lation lof a replacement pump 2|, is desired, the pump to be installed is inserted into the upper end of the supply tubing I1 through the pump head 29. The operator then sets the handle '30 controlling ,the valve means in the pump head 29 in a position such that the supply tubing I1 is placed in fluid communication with the v'supply line 3| and the return tubing I8 is placed in communication with the return line f32. Thus,

the operating fluid under pressure entering the system through the supply 'line 3| acts von the upper end of the pump 2| `to move 'it downwardly throughthe supply tubing |1 and into its operating position in the -pump receiver 20 wherein it is Vseated on the inlet fltting 12, the operating' uid previously introduced below the pump during the pump-removal operation beingr displaced upwardly through the return tubing I8 and into vthe return line 32 leading to the reservoir on the surface. During the operation of installing the pump, the valve 94, or the valve means in the pump head 29, preferably prevents flow through the production tubing I9 and the `production line 33 so that all of the fluid employed yduring lthe pump-removal operationis returned'to the reservoir 'during the freinstallation of the pump.

However, it will Ybe understood that if the -operating Iiuid in the lsupply tubing has become contaminated prior to reinstallation of the pump 2| for any reason, returning such contaminated operating fluid to the reservoir maybe `avoided by preventing fluid ilow through the return Ytubing I8 Yand by permitting uid ilow through :the productiontubing 9.

As will be apparent, one advantage of the embodiment hereinbefore discussed is that it is possible to remove and reinstall the pump 2| lwith substantially no loss of operating fluid `from the system, the production tubing I9 being risolated from that portion of the system reserved for the operating fluid during both the pump-removal operation and the pump-installation operation.

It Awill be noted also that since the production fluid comes in contact with only the interior of the production tubing I9, because of the 'fact that the 'supply and return tubings |1 and `I8 are located without the production tubing, parain control is simplied and damage tothe system "by the action of any Ycorrosive substances which maybe present in the production iluid is minimized, s uch corrosion damage being restricted to the production tubing.

*'lurningV now to the embodiment of the Vinvention which is illustrated in Figs. 5 to 8 of the drawings and referring particularly to Fig. thereofJ the numeral I5 designates a well casing which is set in an oil well and which is open at its lower end to an oil producingzone of the Well as is well known in the art, the casing vbeing provided with ,a casing head IIS at its upper end. vSet in the well within the casing |'|5 Vand connected to the casing head I I6 is a closed tubing system which comprises supply, return and production tubings respectively designated :by the numerals 'I|1, I|8 and IIS. The supply tubing |11 yis disposed concentrically within and spaced from the production tubing IIS and the return tubing vII8 is set beside the production tubing.

The-tubings dIII, |8and IIS are interconnected :at itheir lower A'ends Yin iiui'd communication with teach-othlerand'with the'we'll by a tubular pump receiver "|20 which is aligned with and which, in effect, forms a downward extension of the lsupply tubing I1. The pump receiver |2`|| provides an operating position for a fluid-operated, free pump .I-2I which is movable downwardly lthrough thesupp'ly tubingV II1 into its operating position 'in the pump receiver, the internal diameter o'f the pump receiver being substantiallyequal to thatof the supply tubing. As in the .previouslydiscussed embodiment, the supply tubing'lIlI-1 :is adapted to convey operating fluid 4under=pressure downwardly in the well to the "pump '|2| to actuate the pump, and the 're- -rturn tubing I'I8 is adapted to convey spent operating fluid discharged by the pump upwardly in the well. 'TheQpump 12| is adapted to receive well uid from the Well and to discharge it into 4the production tubing H34 as lproduction fluid, the productiontubing'then conveying the produc- :tion iiuidl upwardly lto lthe surface.

As 4Yin the previously described embodiment, thelowe'r lends 'o'f the tubingsi||1`to H9 and the pump :receiver IZB may be enclosed by a gas anchor 5|-22having a perforated barrel |23 which is closed at 'its upper and lower ends by heads |24 and |25, respectively, the upper head having suitable openings therethrough for the tubings. Thelgas vanchor |22 is secured to the pump re- -ceiver '|,20by fa'bolt |26.

The supply, return and production tubings I |1, 8 fand ||9 fare yconnected at their upper ends 'to-a pump head |29 which is similar to the pump head 129,'the pump head |29 having valve means (not shown) therein which is operable by 'a handle v|30 to direct vflows of fluid through the tubings in the proper manner. Supply, return land production lines |3|, |32 and |33 are also connected to the pump head |29 and are adapted to 'beconnected in fluid communication with the supplyQreturn and production tubings |I1, IIB and I I9, respectively, by the valve means in the pumpjfhead during operation of the pump |2I. As -in'the'preceding embodiment, the supply line 'I3'I leads to a suitable lsource of operating duid vunder pressure, the return line |32 leads to a rreservoir for the source and the production line |33 leads to ra vsuitable point of disposal for the production fluid.

Referring 'now to Figs. 1 and 8 of the drawings, the pump receiver I2 is aligned with the lower end of the Vsupply tubing ||1 and is connected to the lower :ends of the supply and production 'tubings `II1 and H9, the pump receiver having latitsnpper -end a sleeve MQ which is threaded ontothe lower end of the supply tubing. The lower end of the sleeve |48 is tapered and is seated on a tapered seat |40a in the upper end of a major bore |4| in an upper fitting |42 which :forms part of the pump receiver |29, the lower end of the production tubing being threaded onto a cylindrical vprojection |43 on the upper fitting. AThreaded into the lower end of the major bore '|4I isa sleeve |44, the lower end of this sleeve lbeing threaded into the upper end of a major bore |45 in a lower tting |45 which also formspar't of the pump receiver. Encircling and 'spaced from the sleeve |54 Vis another sleeve I41'whichis telescoped over a cylindrical projection |48 at the lower end of the upper tting |42 and overa cylindrical projection |49 at the yupper end of the lowerftting |46, the sleeve |41 carrying sealing rings |50 which engage the projections |48 and |49 in a fluid-tight manner. 'I'his construction permits sliding movement 'of the outer sleeve 41 relative to the upper and lo'wer fittings |42 and |46 as the inner sleeve |44 is threaded into such fittings during assembly. Threaded into the lower end of the major bore |45 in the lower fitting |46 is an inlet sleeve |5| which communicates at its lower end with the well through the perforated gas anchor barrel |23.

The upper fitting |42 of the pump receiver |20 is provided with a minor bore |54 which is spaced laterally from the major bore |4|4 therein, the lower end of the return tubing 8 being threaded into the upper end of this minor bore. The minor 'bore |54 communicates with the interior of the tubular pump receiver I 2|! through a lateral passage |55 in the upper fitting |42. The upper litting |42 is also provided with one or` more longitudinal passages |56 therethrough which communicate at their upper ends with the interior -of the production tubing H9, i. e., which communicate at their upper ends with the annular space between supply and production tubings, and

'which communicate at their lower ends with an l annular space |51 between the sleeves |44 and |41, this annular space being sealed at its ends by the aforementioned sealing rings |50. Pro- 'duction fluid discharged by the pump |2| enters the annular space |51 in a manner to be discussed hereinafter and iiows upwardly through the longitudinal passages |56 into the productionv tubing H9. It will be apparent that, with the foregoing construction, the pump receiver |20 interconnects the supply, return and production tubings ||1, ||8 and 9 in fluid communication with each other and with the well.

'Ihe embodiment under consideration is provided with a passage means |58 for applying a downward flow of fluid through the return tubing ||8 to the lower end of the pump |2| toxunseat the pump and move it upwardly out of the pump receiver |20 when removal of the pump is desired for any reason, the passage means |58 including a tube |59 which is threaded at its upf f per end into the lower end of the bore |60 communicating with the minor bore |54 in the upper tting |42. The lower end of the tube 59 is threaded into the upper end of a bore |6| adjacent the major bore |45 in the lower tting |46, the bore |6| communicating with an annular chamber |62 within the pump receiver |20 at the lower end of the pump |2|l through lateral passages |63, an annular groove |64 and a lateral passage |65. In practice, instead of forming the bore 6| directly in the fitting I 46, 'I prefer to form this bore, the lateral passages |63 and the groove |64 in an insert |65 which is disposed in a bore |61 formed in the lower fitting proper, the tube |59 being threadedly connected to this insert and the insert carrying sealing rings |68 above and below the annular groove |64. This construction facilitates assembly of the upper and lower fittings |42 and |46, the inner and outer sleeves |44 and |41 and the tube |50 since the insert |66 may slide in the bore |61 as the inner sleeve |44 is threaded into the upper and lower `fittings. Y Y

Disposed in the lower end of the majorbore |45 in the lower fitting |46 and extending downwardly into the inlet sleeve |5| is an inlet fitting |12 for the pump |2|, the latter having aninlet which is adapted to receive well fluid fronisithe well through the inlet fitting whenxthe pump-is in its operating position. As vis well knownin' the ff it is disposed in the pump receiver |20 and seated on'` the pump seat provided by the inlet fitting. The pump 2| is adapted to seat on the inlet fitting |12 automatically when it is moved downwardly through the supply tubing |I1 into the pump receiver |20 so that it automaticallyr assumes its operating position.

The pump |2| is substantially identical to the pump 2| and includes a motor section which is actuable by operating iiuid under pressure delivered thereto through the supply tubing |1, the operating fluid under pressure being adapted to enter the motor section of the pump through an intake |18 which comprises ports formed in a iitting |19, carried by a tubular rod |80 which eX- tends upwardly from the motor section of the pump. The rod |80 is adapted tov deliver the op# erating iiuid under pressure entering the intake |18 to the motor section of the pump |2|. After the operating fluid admitted to the motor section' of the pump |2| in this manner has actuated the pump, itis discharged from the motor sectionl through ports forming an exhausty |8| l of the pump. The exhaust |8| communicates with an annular space |82 between the pump and the upper fitting |42 of the pump receiver 20 when the pump is in its operating position, the annular space |82 communicating with the return tubing ||8 through the lateral passage |55 and the minor bore |54 in the upper fitting. Thus, the operating iiuid under pressure in the supply tubing ||1 hows through the motor section in the. pump |2| to actuate the pump and is discharged into the return tubing |8 as spent operating' fluid.

The embodiment under consideration includes sealing means for preventing direct flow between the'suppl'y, return andv productionA tubingsv Y| |1, ||8 and ||9 when the pump 2| `is in its operating position, such sealing means comprisingannular sealing elements |86 and |81 which are carried by the pump respectively above andibelow the exhaust |8| and which are adapted-to engage the upper fitting |42 respectively above and below the lateral passage |55 when the pump is in its operating position. This arrangement places the annular sealing element |86 between the intake |18 and the exhaust 8|. Thus, the annular sealing elements |86 and |81 isolate the intake |18 and the exhaust 8| when the. pump |2| is in its operating position so thatthe intake may communicate only with the supply tubing ||1 and' so that the exhaust may communicate .only with the return tubing ||8.

As previously mentioned, the pump section of the pump 2| is provided with an inlet at its annular space |89 communicates with the annular yspace |51 between the inner .and outer sleeves |44 and |41 through ports |90 so that production fluid discharged by the pump section of the pump |2| through the outlet |88 enters the production tubing ||9 by way of the annular space |39, the ports |90, the annular space |51 and the longitudinal passage or passages |56.

In order to prevent the production iiuid discharged through the outlet |88 into the annular space |89 from mixing with the spentl operating iluid in the annular. chamber |62 at the lower end of the vpump |2|, the pump carries an annular sealing element |94 which is disposed below the outlet and which engages a liner .|95 in the major bore |45 in the lower fitting |46 when thepump is in its operating position. Thus, the annular sealing element |94 serves to isolate the outlet |88 from the return tubing so that it communicates only with the production tubing when the pump is in its operating position. A1- so, since the pump is seated on the inlet tting |12 when it is in its operating position, the pump seat provided by the inlet tting serves to prevent direct iiow between the well and the return tubing ||8.

Considering the operation of the embodiment disclosed in Figs. to 8 of the drawings, it will be assumed that the pump |2| is in operation to pump fluid from the well upwardly through the production tubing |19 to the surface. Under such conditions, the pump is .in its .operating position in the pump receiver |20 wherein itis seated on the inlet fitting |12, and the aforementioned valve means in the pump head |29 respectively connects the supply, return and production tubings ||1, ||8 and ||9 to the supply, return and production lines |3|, |32 and |33. Thus, operating fluid under pressure is carried downwardly to the pump |2| lthrough the supply tubing ||1 and enters the motor section o f the pump through the intake |18 to actuate the pump, the spent operating fluid being discharged into the return tubing ||8 through the exhaust |8| and being conveyed upwardly in the well to the surface by the return tubing. The well fluid entering the pump section of the pump |2| through its inlet is discharged into the production tubing V||9 through the outlet |88 and is conveyed upwardly in the `Well Aseparately from the spent operating fluid.

Whenever removal of the pump |2| is desired, the 4operator sets the handle |30 controlling the valve means in the pump head |29 in a position such that the valve means connects the supply line |3| to the return tubing .l |B so that Operating lfluid Aunder pressure flows .downwardly in the well through the return tubing. Preferably, the valve means also connects the supply tubing |'|1 to theA return line |32 so that operating uid above the pump |2| may be returned to the vreservoir. In order to prevent'ow -of operating iluid into the production tubing I9, flow Athrough the production tubing and the production .line |33 is preferably prevented, as by closing a valve |96 in the production line, or by means of the valve means in the pump |29.

Under the conditions outlined 'in the preceding l paragraph, operating lluid under pressure ilows downwardly through the return tubing ||8 and into the annular chamber |62 at the lower end of the pump |2|' by way of the passage lmeans 1.58 vand acts on an annular area |91 at the lower end of the pump so as yto unseat the pump lfrom the linlet fitting |12 and `then acts on 'the entire area of the pump so as to move it upwardly in the `pump receiver itt, .the various annular sealing elements carried by the pump preventing upward flow of the operating uid past the pump.h After the pump |2| has moved upwardly in the pump receiver ii a distance Such that annular sealing elements and |81 disengage the wall of the-major bore HH and such that the annular' sealing element |94 disengages the liner |95, upward iiow of operating fluid past the pump is prevented by packing devices ISB and |99 carried by the rod |80. The packing devices |98 and 95 are adapted to engage the inner wall of the supply tubing ||1 in a substantially fluid-tight manner, the portions of the pump which carry the annular sealing elements |80, |81 and |96 preferably being of smaller diameter than the internal diameter of the supply tubing so as to prevent damage to the sealing elements during l @vement of the pump through the supply tubing.

It will be noted that after the pump |2| clears thev lateral passage |55 in the upper fitting |42, the downward iiow of operating iiuid through the return tubing H3 may enter the interior of the pump receiver |29 through such lateral passage. Continuing downward iiow of operating iluid under pressure through the return tubing H8 ultimately results in upward movement of the pump |2| through the .supply tubing 'i i1 to the surace so .that it may be removed from the supply tubing through the pump head |29, the operating fluid in the supply tubing above the pump being displaced into the return line |32 under the conditions specified. During the foregoing pump-removal operation, flow of the operating iluid employed to remove the pump downwardly into the well is prevented by the check valve in the inlet fitting i12.

When reinstallation of the pump |2| is d'esired, the pump may be inserted into the upper end of the supply tubing ||1 through the pump head |29. The operator then sets the handle |30 controlling the valve means in the pump head in a position such that the supply tubing is placed in uid communication with the supply line E31 and the return tubing ||8 is placed in fluid communication with the return line |32. Preferably, the production tubing H9 remains closed, as by means of the Valve in the production line |33, or by means or" the valve means in the pump head lZ. Under such conditions, the operating fluid under the pressure entering the 'system through the supply line ii acts on the upper end of the pump 2i to move it downwardly through the supply tubing and into its operating position in the pump receiver |2|] wherein it is seated on the inlet tting |12. The operating fluid previously introduced below the :pump during the pump-removal operation may be displaced upwardly through the return tubing IIS so as to be returned to the reservoir for re-use. However, it will be understood that if operating fluid in the supply tubing has become contaminated prior to reinstallation of the pump |2| for any reason, returning such 'contaminated operating fluid to the reservoir may b'e avoided by preventing fluid now through lthe vreturn tubing ||8 and by permitting fluid new Y withsubstantially no loss of operating iiuid from the system, Athe production tubing 'i i9 being isolated from that portion of the system reserved for the operating fluid during both the pumpremoval operation and the operation of reinstalling the pump, as long as the valve 594 in the production line |33 remains closed.

While the embodiment under consideration has one disadvantage in that it permits the production fluid to come in contact with both the supply and production tubings, it has an important advantage in that it permits the use of a production tubing of relatively large diameter so as to minimize frictional losses between the production stream and the production tubing, which is important in wells permitting the use of a pump having a pump section of large capacity and a motor section of small capacity.

Although I have disclosed exemplary embodiments of my invention herein for purposes of illustration, it will be understood that I do not intend to be limited specifically thereto since various changes, modifications, and substitutions may be incorporated in such embodiments without departing from the spirit of the invention.

I claim as my invention:

1. VIn a. closed, Huid-operated, free-pump system for a well, the combination of supply, return and production tubings set in the well and respectively adapted to convey operating fluid downwardly into the well from the surface, spent operating iiuid upwardly in the well to the surface and iluid produced by the well upwardly thereinl to the surface, one of said tubings being disposed within another of said tubings which encloses said one tubing; means for intercon-` necting the lower ends of vsaid tubings in fluid communication with each other and with the well; and a fluid-operated free pump movable in oneof said tubings other than said enclosing tubing into an operating position at the lower end thereof said pump having an intake, an exhaust, an inlet and an outlet which communicate with said supply tubing, said return tubing, the well and said production tubing, respectively, when said' pump is in said operating position.

2. Ina closed, fluid-operated, free-pump sys'- tem for a well, the combination of: three tubings set in the well and respectively adapted to convey operating iiuid downwardly into the well from the surface, spent'operating iiuid upwardly in the well to the surface and fluid produced by the well upwardly-therein to the surface, at least one offs'aidtubings being disposed withinanother of said tubings which encloses said one tubing; means for interconnecting the lower ends of said tubings in fluid communication with each other and with the well; a pump seat at the lower end of and aligned with one of said tubings other than said enclosing tubing; and a fluid-operated, free pump movable in the tubing having said pump seat at its lower end into an operating position wherein said pump is seated on said pump seat, said pump having an intake, anex- A haust and an outlet which communicate with said tubings, respectively when said pump is in said operating position, and having an inlet which communicates with. the well when said pump is in said operating position. 3. In a closed, fluid-operated, free pump system fora well, the combination of supply, return and production tubings set in the well and respectively adapted to convey operating fluid downwardly into the well from the surface, spent operating fluid upwardly in the well to the surface and iiuid produced by the well upwardly therein to the surface, one of said tubingsbeing disposed within another of said tubings which encloses said one tubing; a tubular pump receiver at the lower end of and aligned with one of said tubings other than said enclosing tubing, said pump receiver being connected to the lower ends of said tubings in fluid communication therewith and being in fluid communication with the well; and a fluid-operated, free pump movable in said tubing having said pump receiver aligned therewith and movable into an operating position in said pump receiver, said pump having an intake, an exhaust, an inlet and an outlet which communicate with saidl supply tubing, said return tubing, the well and said production tubing, respectively, when said pump is in said operating position in said receiver.

4. Aclosed system as set forth in claim 3 including sealing devices for normally preventing direct flow of fluid between said tubings and the well when said pump is in said operating position.

5. In a closed, fluid-operated, free-pump system for a well, the combination of: supply, re-

turn and production tubings set in the well and` 'tubing with which it is aligned, and said pump receiver having' passages which provide fluid communication between the others of said tubings andsaid pump receiver and between the well and said pump receiver; a pump seat carried by said pump receiver at the lower-end thereof and in alignment therewith; a fluid-operated, free pump movable in the tubing with which said pump receiver is aligned and movable into an operating position in said pump receiver wherein it is seated on said pump seat, said pump having an intake. an exhaust, an inlet and an outlet which communicate with said supply tubing, said return tubing, thewell and said production tubing, respectively,` when said pump is in said operating position; .and sealing devices for normally preventing direct flow of fluid between said tubings and the well by way of said pump receiver when said-pump is in said operating position.

6. In Aa closed, fluid-operated, free-pump system for a well, the combination of supply, return and production tubings set in the well and respectively adapted to convey operating fluid downwardly into the well from the surface, spent operating iiuid upwardly in the well tothe surface andv fluid produced by the Well upwardly therein-'sto the surface, one of said tubings being disposed within another of said tubings which encloses said one tubing; a tubular pump receiver connected to the lower ends of said tubings in alignment with one of said tubings other than said enclosing tubing, said pump receiver communicating at its upper end with and having substantially the same internal diameter as the tubing with which it is aligned, and said pump receiver having passages which provide fluid communication between the others of said tubings and said pump receiver and between the well and said pump receiver; a pump seat carried by said 19E pump: receiver at. the lowerend? thereofV andin4 alignment therewith; afluidi-operated',` free-pumpvv movable inthe tubingv with which. said. pumpree. ceiver is. aligned and movable into an operating;

position in said pump receiver whereinl it. i's; 5

seated on said pumpseat, said pump having an intake, Vanexhaust, an inlet andan outletwhich communicate with said: supplytubing, said re turn. tubing, the well and said' production. tubeing, respectively, when4 saidpump is in sa-idopit erating position; sealing devices for normally.-

preventing direct flow` of fluid between said tub-J ings and the well by way,`r of said pumpT receiver.- when: said pumpisinsaid operating position; a. chamber in said pump. receiver between said pump seat and said pump; and'. passageL means.

providing iiuid communicationbetween saidv chamber: and. one of 'the tubings which are-not aligned with said pump-v receiver so as to deliver fluid flowing: downwardlythrough said one non.I

aligned tubing to said chamber to move said pumpupwardly out of! said pump receiverand through the tubing in registry with said pum-p; receiver to` the surface.

7; Ina closed, fluid-operated, free-pumpsystem for aY well, the combination of: supply, re-V n turn. and? procurationI tubings set, in the well and respectively: adapted to convey operating uid downwardly into 4thewell fromY thesurface, spentl operating fiuid upwardly in the well tothe sur-- tem fior. a. we1l, the combination of: supply.. ref

.turn andi production tubings setin thewellv and' respectively adapted to convey operating fluidiv downwardly into the well fromthe surface, spent operating fluid upwardly. in the well to the: surface and fluid produced byv the well upwardly therein. to the surface, one ofi said tubingsv being disposed within another of 'said tubings; means.

for interconnecting the lower ends of saidi tub ings4 in fluidv communication. with each other andL with thevwell; a huid-operated; free pump mov'- able in said one tubing intov an operatingl posi@ tion at thelower-end thereof, said pumphaving an.y intake, an exhaust, an inlet and an outlet which communicate with said supply tubing, saidlposition through said one tubing-to the surface.

face and. duid produced by t-ewell upwardly z thereinto the surface, one of said tubingsbeingdisposed withinY another of said tubingswhich encl'osesV said one tubing; a tubularpump receiverconnected to the lower ends ofl saidtubingsin alignment with one ofA said` tubings other' thanV saidv enclosing tubing, said pump receivercommunicating at its upper end with and having substantially the same internal diameter as the tubingwith which it is aligned, and said pumpreceiver having passageswhich provide fiuid4 communication between theL othersv of said tubings4 and said pump receiver and between the well and said pump receiver; a pump seat carried bysaid' pump receiver at the lower end thereofv and in alignment therewith; a fluid-op erated, freel pump movable in the `tubing with-1 which: saidpump-.receiveraligned and'movableintoan operating position in said pump receiver wherein itis seated on said pump seat, said pumphaving' anintake, an exhaust, an inlet and an outlet which communicate with said supply tub-y ing, said' return tubing,vthe Welland saidA produc tion tubing, respectively; when said: pump'is said operating position; sealing devices fornormally preventing direct flow: of luidv between-said tubings. andthe well byf way. ofsaid pump receiver: when said pumpis in said operatingposition; a. chamber in said. pump. receiver betweensa-id' pump'fseat; and said pump; passagemeansrpro viding'fiuid` communication between said cham. ber; and` one of thetubings whichare not-,aligned with; saidi pumpv receiver so asv to deliver fluid lowingjdowrrwardly throughsaid one nonaligned. tubing; to said chamber to move said pump-up-` wardly out of said pump receiver. and through. the: tubing. in registry with said' pump-receivertothe4 surface;A and;another.I sealing device for' noremally preventing flow of fluid betweensaidv pas@w sage `means and said productiontubing.

8. A` closed' system as` set. forth in` claim 7' wherein said other. sealing device comprises.- an` annular-sealing element adapted-.to be positioned between said? pump andsaid. pump receiver.

9g. In a.. closed, iiuidfoperated, free-pump-sys 751. sad pumpreceiver whensaidpumpis-insaidl0.` AA closed syst'enias` set forth in claim 9 wherein said one tubing issaid supply tubing;

11. A closed system as set forth in cla-im 9l wherein said-one other tubing with which said passageI means communicates is said return tubing'. j 1-2 A closed` system as setforth in claimy 9' y.whereinrsaidsupply andreturn tubings are-without-saidv production tubing".

- -13.,A closed system` as set forth in claim 9 wherein said one tubing is off largery diameter than one-of the others of said tubings;

14'. A closed system according to claimY QWhereingsaid production tubing is of larger diameter-A than atleast one off the others-of; said tubings.

151A closed systemy as dened in claim 9 wherein said'- production tubing is of larger diameter than either of-the other two tubings.

16; A closedjsystem according, to claim 9 whereposed is located beside the other of said'tubings;

IS7.'4 In a closed, fluid-operated, free-pump sysi, teni for' a well, the; combination ofzsupply, re-

turn and, productionl tubingsset in the Wellandrespectively adapted' to convey operating fluidv downwardly-urto lthe-well from the,l surface, spentoperating fluid',` upwardly-inv the well to thesure faceand-fluidproducedby-4 the well upwardly-- :j thereinV to the surf-ace, said supply tubing beingiff-1l disposed-within one ofthe others-of said tubings;; y a` tubular; pump receiver atthe lower end of` an register-ing with said-supply-tubing, saidpump recei'ver beingv connected to the lower ends of said tubingsl andbeingin fluid 'communication with said? tubings andlwith the-well; a pump seat carried-.bysaid pump receiver and disposed atthe lower end thereof in registry therewith; a fiuidoperated, freepump movable in said supply tub-1- ing and? movable into anl operating position insaid pump receiverwherein it: is seatedon saidpump seat, said: pump having-an intake, an exhau'st,A an-inletand an outletf which communicate'iwithsa'id supply tubing, said return tubing, thefwell' and-said production tubing, respectively, when: said-y pump-isV inysaid oper-ating position;` meansfornormally preventing direct iiow ofi fiuidrbetweensaid tubings andn the well through operating position; and passage means communicating with one of said other tubings and with said pump receiver above said pump seat for applying a downward iiow of fluid in said one other tubing to the lower end of said pump to move it upwardly out of said pump receiver and through said supply tubing to the surface.

18. A closed system as set forth in claim 17 wherein said passage means communicates with said return tubing and wherein said means for normally preventing direct flow comprises a sealing device for preventing fiuid communication between said return tubing and said production tubing when said pump is in said operating position.

19. A closed system as set forth in claim 18 wherein said sealing device comprises an annular Cil sealing element adapted to be positioned between said pump and said receiver.

20. A closed system as set forth in claim 17 wherein said supply tubing is disposed within said return tubing.

21. A closed system as set forth in claim 17 wherein said supply tubing is disposed within said production tubing.

22. A closed system as set forth in claim 17 wherein said supply tubing is of larger diameter than one of the others of said tubings.

23. A closed system as set forth in claim 17 wherein said production tubing is of larger diameter than one of the others of said tubings.

24. A closed system as set forth in claim 17 wherein said production tubing is of larger diameter than either of the others of said tubings.

25. In a closed, fluid-operated, free-pump system for a well, the combination of: supply, return and production tubings set in the well and respectively adapted to convey operating fiuid downwardly into the well from the surface, spent operating iiuid upwardly in the well to the surface and uid produced by the well upwardly therein to the surface, said supply tubing being disposed within one of the others of said tubings; a tubular pump receiver at the lower end of and aligned with said supply tubing, said pump receiver being connected to the lower ends of said tubings in iiuid communication therewith and being in fluid communication with the well; a Huid-operated, free pump movable in said supply tubing into an operating position in said pump receiver, said pump having an intake, an exhaust below said intake, an outlet below said exhaust and an inlet below said outlet, said intake, said exhaust, said inlet and said outlet respectively communicating with said supply tubing, said return tubing, the well and said production tubing when said pump is in said operating position; an annular sealing element carried by said pump intermediate said intake and said exhaust and engageable with said pump receiver when said pump is in said operating position; another annular sealing element carried by said pump intermediate said exhaust and said outlet and engageable with said pump receiver when said pump is in said operating position; and sealing means providing a duid-tight seal between said inlet and said outlet when said pump is in said operating position.

26. A closed system according` to claim 25 including a passage communicating at one end with said return tubing and at its other end with said pump receiver at a point which is intermediate said other annular sealing element and said sealing means when said pump is in said operating position, said system including a sealing device for normally preventing flow from said return tubing through said passage to said production tubingV when said pump is in said operating position.

27. A closed system as set forth in claim 26 wherein said sealing device comprises an annular sealing element carried by said pump and engageable with said pump receiver.

28. In a closed, fluid-operated, free-pump system for a well, the combination of: supply, return and production tubings set in the well and respectively adapted to convey operating uid downwardly into the well from the surface, spent operating fluid upwardly in the well to the surface and fluid produced by the well upwardly therein to the surface, said supply tubing being disposed within one of the other tubings and the second of the other tubings being disposed without and beside said one other tubing; means for interconnecting the lower ends of said tubings in fluid communication with each other and with the well; and a iiuid-operated, free pump movable in said supply tubing into an operating position at the lower end thereof, said pump having an intake, an exhaust, an inlet and an outlet which communicate with said supply tubing, said return tubing, the well and said production tubing, respectively, when said pump is in said operating position.

29. A closed system as set forth in claim 28 wherein said one other tubing and said second other tubing are said return tubing and said production tubing, respectively.

30. A closed system as set forth in claim 28 wherein said one other tubing and said second other tubing are said production tubing and said return tubing, respectively.

31. In a closed, duid-operated, free-pump system, the combination of a primary tubing and a pair of secondary tubings set in the well with one of said secondary tubings enclosing at least one of the other two tubings, said primary tubing being of a size to receive a fluid-operated, free pump and providing for movement of the pump between an operating position at the lower end of said primary tubing and the surface; means interconnecting the lower ends of said tubings, said interconnecting means having passage means providing uid communication between one of said secondary tubings and said primary tubing and having passage means providing fluid communication between the other of said secondary tubings and said primary tubing; and inlet means connected to said primary tubing and having a passage providing uid communication between the well and said primary tubing, said inlet means having means for preventing flow of fluid from said primary tubing into the well through said passage.

CLARENCE J. COBERLY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,630,902 Parrish May 31, 1927 1,765,921 Joy June 24, 1930 2,162,748 Richards et al June 20, 1939 2,230,787 Swain Feb. 4, 1941 2,230,830 Coberly Feb. 4, 1941 2,277,181 Zuck Mar. 24, 1942 2,338,903 Coberly Jan. 11, 1944 

